The history of concrete is a long and fascinating one, stretching back thousands of years. It was the ancient Romans who first discovered the properties of concrete, mixing limestone with water and volcanic pozzolana to create a semi-liquefied mixture that could be poured into wooden molds to create strong and smooth pieces. This same method is still used today, although modern engineers often use steel instead of iron for reinforcement. In 1824, an Englishman named Joseph Aspdin invented Portland cement by burning chalk and finely ground clay in a kiln until carbon dioxide was removed.
He named cement after high-quality building stones mined in Portland, England. This invention gave concrete a new life, as it was now possible to reinforce it with iron or steel rods. California engineer Ernest Ransome began testing 2-inch concrete and iron rods to see if materials adhere, and when they did, he went one step further by twisting the iron rods to create armor around which he could “build concrete in any desired shape” - an experiment that also worked. Nowadays we call this system rebar or reinforced bar. The invention of reinforced concrete gave the material a new life.
It was pioneered in France in the mid-19th century, but was popularized by California-based engineer Ernest Ransome, who poured onto iron (and later steel) bars to improve their tensile strength. The world record for the largest concrete pouring in a single project is the Three Gorges Dam in Hubei Province, China, by Three Gorges Corporation. Some concrete house projects were launched in the US Department of Commerce, including what became known as Cement City in Donora, south of Pittsburgh, but the dream of cheap and spacious concrete houses never really took off. Concrete is expected to be a key material for structures resistant to climate disasters, as well as a solution to mitigate pollution from other industries, capturing wastes such as coal fly ash or tailings and bauxite residues. Reducing the content of cement clinker could have positive effects on the environmental assessment of the concrete life cycle.
Architect Frank Lloyd Wright had to realize the potential of reinforced concrete to create completely new forms. Another approach to mass concrete structures that minimizes the thermal by-product of cement is the use of roller-compacted concrete, which uses a dry mix that has a much lower cooling requirement than conventional wet laying. In general, modern concrete can last around a century without major repairs or replacements, according to Concrete Planet. Any interruption in concrete pouring may cause the initially placed material to begin to set before the next batch is added to the top. In prestressed concrete, prestressing is achieved through the use of steel or polymer tendons or bars that are subjected to a tensile force before casting, or for post-tensioned concrete, after casting. Modern paving methods and design practices have changed the economics of concrete paving, so that a well-designed and laid concrete pavement will be less expensive in initial costs and significantly less expensive over the life cycle. The Colosseum was completed 1937 years ago, and today stands as one of the enduring symbols of the Roman Empire and, more literally, as a testament to the strength of Roman concrete.
In Cincinnati in 1903, the Ransome system made possible the first concrete skyscraper, the 16-story Ingalls Building. Ransome himself did not participate in the construction of this structure but it would not have been possible without his rebar method (rebar).Concrete has come a long way since its invention by Joseph Aspdin in 1824. Today it is used for everything from skyscrapers to roads and bridges - all thanks to its incredible strength and durability. It is expected to be an important material for structures resistant to climate disasters and for mitigating pollution from other industries.
